Slam-style safety lock

ABSTRACT

A slam-style safety lock for industrial refrigerated walk-in compartments, truck bodies, and self-sealing environmental rooms, to allow egress from the interior when the lock is secured on the outside. The lock bolt is retractable, being actuated by a pivotal handle in the well known manner, and the bolt has a centrally positioned aperture in which is positioned a cam hub which engages a shoulder at the rear of the bolt, the shoulder acting as a cam follower. The forward portion of the bolt has a rear lip under which is positioned a forwardly extending metal locking plate, also having a shoulder positioned just forwardly of the front surface of the cam hub. Positioned under the plate is a leaf spring maintaining constant pressure on the locking plate to actuate a drop action when locking is required.

United States Patent [1 1 Loikitz Jan. 22, 1974 SLAM-STYLE SAFETY LOCKFrank F. Loikitz, Middletown, NJ.

Assignee: Instrument Systems Corporation,

' Jericho, NY.

Filed: Jan. 12, 1972 Appl. No.: 217,148

Inventor:

[52] US. Cl 70/150, 292/153, 292/169.14,

292/DIG. 31 Int. Cl E051) 65/06 Field of Search.. 70/150, 151 A, 208;292/152,

292/153, 169.14, DIG. 31, DIG. 71

[56] References Cited UNITED STATES PATENTS 12/1952 Adams et a1 70/1468/1966 Chesler 70/150 Primary ExaminerAlbert G. Craig, Jr. Attorney,Agent, or Firm-Meyer A. Gross [57] ABSTRACT A slam-style safety lock forindustrial refrigerated walk-in compartments, truck bodies, andself-sealing mag a ,i

environmental rooms, to allow egress from the interior when the lock issecured on the outside. The lock bolt is retractable, being actuated bya pivotal handle in the well known manner, and the bolt has a centrallypositioned aperture in which is positioned a cam hub which engages ashoulder at the rear of the bolt, the

shoulder acting as a cam follower.

The forward portion of the bolt has a rear lip under which is positioneda forwardly extending metal locking plate, also having a shoulderpositioned just forwardly of the front surface of the cam hub.Positioned under the plate is a leaf spring maintaining constantpressure on the locking plate to actuate a drop action when locking isrequired.

In an unlocked position the plate is depressed inwardly so that the boltpasses along the plate without contacting it. When the lock is in asecured position rearward movement of the bolt will cause the forwardportion of the plate to engage the lip on the bolt. If the cam hub isactuated from within, upon rotation, the forward surface of the hub willstrike the shoulder of the plate, causing the plate to be depressedinwardly, and allowing the bolt to move rearwardly 8 Claims, 7 DrawingFigures PATEIEU JAN 2 2 mm SHEU 1 0F 2 SLAM-STYLE SAFETY LOCK BACKGROUNDOF INVENTION The present invention relates to safety locks, and moreparticularly to a slam lock mechanism having unique structure to by-passouter security locks from within.

Industrial refrigerator compartments utilize gasketed swing doors orself-closing doors with standard slamtype latches, the bolt catching thekeeper or strike when the door is slammed shut. Because of the design ofthese compartments, the doors usually slam shut when someone enters theinterior, and there are means on the inside of the compartment to causethe bolt to be retracted when someone wishes to leave the compartment.

Due to the value of merchandise in the enclosure, all such units containmeans to lock the box for prevention of unauthorized entrance. Usuallysuch security means consist of cylinder locks or padlocks, or both.However, if someone is accidentally caught in the interior after thelocks have been secured, the results could be fatal. Complicatedinvolved means have been developed in the past to by-pass the esteriorlocks, and allow the bolt to be retracted from the interior.

INVENTION Accordingly, among the principal objects of the presentinvention is to provide a new and novel by-pass construction which willallow egress from the interior of a box when the exterior locks havebeen actuated, all with a resultant overall economy of design.

Yet a further object of the present invention is to provide constructionin which the interior actuating means simultaneously releases thecylinder locking means, bypasses the padlock, and retracts the bolt.

Yet another object of the present invention is to provide a simplifiedby-pass structure within a slam-style safety lock, which can bemanufactured and produced on a relatively inexpensive basis, frominexpensive materials, and yet will be durable to a high degree in use.

BRIEF DESCRIPTION OF INVENTION The invention consists of a casing whichis secured to a door by mounting screws. Housed within the casing is ahandle having an exteriorly extending lever, pivoted to the casing.Located inside the casing is a retractable bolt, which is maintained inan outwardly extended position by a compression spring. The exposedportion of the bolt engages a strike in its closed position, the strikebeing mounted on the jamb of the door. The bolt has an inner lip, andthen a centrally positioned aperture defining a rear shoulder, whichacts as a cam follower and is contacted by a cam hub (which willhereinafter be referred to as the hub), pivotally mounted in theaperture and positioned in a seat located in the housing. The hub has anopening to receive a spindle which extends through the door of thecompartment into the interior thereof.

Positioned below the hub is a locking plate having an aperture throughwhich the spindle extends, the plate extending rearwardly and forwardlywith an upwardly extending shoulder just forward ,ofthe front surface ofthe hub, and then an upwardly extending tongue. Positioned below theplate is a leaf spring which maintains upward pressure on the lockingplate.

The locks include a padlock which may be passed through apertures in thecasing and the wings of the handle to prevent pivotal movement of thehandle. The locks also include a cylinder lock having a truncatedcylindrical member designed so that in its unlocked position, thenon-truncated portion of the member engages the forward portion of theplate depressing it and allowing the bolt to move without obstruction.When .the cylinder lock has been actuated to its blocking position, thenon-truncated portion is positioned so as not to depress the plate whichis then urged upwardly, and rearward movement of the bolt causes theforward edge or the tongue of the plate to engage the lip in the bolt,preventing other than nominal movement.

When the cylinder lock has been so actuated and the padlock hasp is inposition, a person on the inside of the box may open the door by simplyrotating the spindle in either a clockwise or counter-clockwisedirection. This will cause the hub to pivot in either direction with itsforward surface bearing against the upward shoulder of the plate,causing the tongue to be depressed, and the rear surface of the hubbearing against the cam follower shoulder of the bolt, allowing the boltto be retracted, thus by-passing the tongue and the padlock.

The above description and objects of the present in vention will becomeapparent from a reading of the following description, taken withreference to the accompanying drawings, in which FIG. 1 is a perspectiveview of an improved slamstyle safety lock embodying the presentinvention, showing the lock on the door (partly cut away) and the keeperon the jamb;

FIG. 2 is an enlarged, side-elevational view of the lock, keeper andlever, with sections cut away;

FIG. 3 is a bottom planned view with the bottom plateremoved;

FIG. 4 is a side elevational view showing the cylinder lock in theunlocked position and with the padlock removed, and the handle partiallyactuated, causing a partial retraction of the bolt;

FIG. 5 is a view similar to FIG. 2 with the interior lever rotated andthe cam hub depressing the tongue and bearing against the cam followershoulder of the bolt;

FIG. 6 is a bottom plan view of FIGS with the bottom plate removed; and

FIG. 7 is an exploded, perspective view of the strike.

Turning to the drawings, and particularly to FIGS. 1 and 2, there isshown an improved slam-style safety lock 10 embodying the presentinvention and broadly comprising a yieldable latch 11, a keeper 12, thelatch and keeper being respectively mounted on a door I4 and a jamb l6,and a lever 18. I

More specifically, the latch is housed in a casing 20 which may be diecast or formed in any other conventional manner.

The casing includes a somewhat rectangular shaped central portion 22which is defined by a top wall 23, sidewalks 24, a front wall 26, and arear wall 28 (FIG. 2). A channel 30 (FIG. 4) is defined in the centralportion, and extends from the front wall 26 to the rear wall 28,.andpartially down the rear wall, ending at edge 32.

A rectangular aperture 34 is also formed in the front wall 26 and around aperture 36 in the top wall 23.

A pair of shoulders 38 extend outwardly from the lower edges of the sidewalls and contain apertures 40 for receipt of screws or bolts 42 tosecure the latch to the door.

Positioned towards the rear of the casing and extending downwardly fromthe top wall 23, is an inverted cup member 44 (FIG. 2) defining areceptacle 46 for the purpose hereinafter appearing.

Also positioned within the central cavity is a post 48 with a threadedbore 50. Covering the entire cavity is a bottom plate 52 having acounter-sunk opening 54, a location dimple 56, and a back edge 58. Thebore 50 and the opening 54 mate and receive a screw 60 to secure thebottom plate 54 and close off the central portion cavity. The bottomplate is flush with the base of the shoulders 38 to insure a proper fitagainst the door.

Turning to FIGS. 4-5, there is shown a handle 64 which is of the pivotaltype and is used to retract the bolt from the strike when the latch isunlocked. The handle includes a gripping portion 66 (which is partiallyshown) to the rear with a forward bottom edge 67 and a forwardly placedpivot 68 which is received in apertures 69 of the handle and inapertures 70 (FIG. 6) within the casing 20. Forwardly of the pivot is adownwardly extending finger 72.

The handle is received within the channel 30 of the casing and in itsnormal position the forward bottom edges 67 of the gripping portion restagainst the edge 32 in the rear wall 26 of the casing 20. The handlealso includes two downwardly extending wings 74. The wings containapertures 76 which are aligned with openings 78 in the casing to allowthe passage of the hasp 80 of the padlock 82 (FIG. I) to provide one ifthe means for locking the latch.

As previously mentioned, the handle actuates a retractable bolt 84. Thebolt extends through a major portion of the casing and includes aforward strike portion 86 with a rear first shoulder 87 causing asubstantial decrease in thickness of the bolt, to an elongated basicallyrectangular portion 88 having a lip 89 (FIG. and then followed by anelongated rectangular twostepped aperture 90 defined therein. Thisaperture is narrower and ends at rear surface 92 of an intermediate rearshoulder 94 which receives the finger 72 of the handle 64.

Emanating rearwardly from the intermediate shoulder 94 is a secondsubstantially rectangular portion 96 having defined therein a rearsemi-cylindrical aperture 98 which terminates in a rear shoulder 100,below which is located a rear cross-member 101 having symmetricalsections 102 as defined from a center line 103. Extending rearwardlyfrom the member and shoulder is a stop bar 104 (FIG. 4) which is alignedwith a bearing shoulder 106 adjacent the rear wall 28 of the casing 20.

The shoulder 106 acts to receive and guide a compression spring 108which encircles the stop 104 and bears against the back wall 28 of thecasing 20 and the rear shoulder 100 and the member 101 urging the bolt84 outwardly to a normal extending position with the handle in alignmentwith the rest of the casing. The bolt is properly guided during itsretractable travel in the casing by means of the forward inner surfacesjust behind the aperture 34 and the front wall 26, as well as the upwardforces from the locking plate.

The bolt is received by the keeper 12 containing a roller 109 engagingthe top surface of the forward portion 86 of the bolt. The keeper may besecured to the door jamb by means of screws or the like. The roller isjournaled in a carriage 110 riding in a channel member 111. The carriageand roller may be adjustably positioned with respect to each other. Thecarriage and rol ler have abutting and mating ridged surfaces 112, 11211and they are held in positive contact with each other by means of screwspassing through opposed elongated slots and received within threadedapertures. Extending downwardly from the roller and enclosing the sameare side guards 112 which completely enclose the forward portion of thebolt. This prevents tampering or forcing the bolt from outside of thedoor.

Extending into the cavity of the casing through the aperture 36 is astandard cylinder lock 114. As shown in FIGS. 2, 4-6, extendingdownwardly from the lock 114 is a cylindrical support 116 carrying adrop action or truncated cylindrical member 118.

More particularly, the member 118 consists of an annular shoulder 120(FIG. 5) from which depends a cylindrical surface 122. At its longestlength the surface extends down to a bottom surface 124 which in the endview (FIG. 3) represents a portion of a circle. Commencing from theforward edge 126 of surface 124, a sloping surface 128 extends upwardlytowards the surface 122, meeting it at edge 130 which is its shortestlength.

Positioned just below the member 118 and extending towards the rear ofthe casing is the locking plate 132 (FIGS. 2, 4, and 5). Morespecifically, it consists of an upwardly extending forward tongueportion 134 terminating in an edge 136. The tongue joins a secondupwardly extending portion 138 at 140, the two portions forming anobtuse angle of greater than 90. The second portion 138 terminates in adownwardly extending shoulder 142 at 144 and then at 146 the tongue hasa portion 148 which extends rearwardly and substantially horizontally,and has an aperture 150 defined therein and terminating at a rear edge152. Located just beneath the tongue is a leaf spring (FIG. 2) 154having an upwardly extending forward portion 155 which extends justforwardly of the joinder 140 of the portions 134, 138; a horizontalcentral portion 156 with an aperture 157 defined therein; and anupwardly extending rearward portion 158, whose rear edge 159 contactsthe rearward portion 148 of the tongue. The purpose of the leaf springis to constantly urge and maintain the locking plate in an upwarddirection, and because of the non-movable mechanism in the rear of thelatch, the force is all translated to the forward portion of the tongue.

The receptacle 46 in the dish 44 is designed to receive a cam hub 160.The hub includes (FIG. 2) a cylindrical body section 162 which isreceived within the apertures 150, 146, and 98. The cam hub alsoincludes two symmetrical arms 164, 166 (FIG. 3 having rear bearingshoulders 168, 170, and a forward bearing shoulder 172. The rearshoulders face the shoulder 101 and the forward shoulder faces shoulder146.

The hub also includes a central aperture 174 which may be non-circularin cross-section and is shown as square. The aperture is designed toreceive a spindle 176 (FIG. 2) of similar cross-section and dimension,which forms a portion of the lever 18. The lever also consists of an arm178, the arm and the inner portion of the spindle being located withinthe interior of the environment when the unit is assembled. The spindleis of sufficient length to pass through the entire door and may have anascutcheon or rose 180 to receive the release lever 18. The lever issecured to the inside of the door by screws (not shown) passing throughthe rose.

Because of the simplified construction of the locking by-pass means, theresultant structure of the entire safety latch is not only moreeconomical, but durable to a high degree in use. FIG. 4 shows the normaloperational position of the cylinder lock 114 when the refrig erator boxis in use. The lock is turned so that the 'surface 124 is to the left,and bears against the forward edge 136 of the plate 132 depressing it.Thus, when the handle 64 is actuated and the finger 72 contacts thesurface 92 of shoulder 94, the bolt 84 passes into the latch withoutmeeting any obstructions until the stop bar 104 contacts the rear wall106. However, the handle 64 allows opening of the door before-thisinward travel position is reached.

In order to lock the door solely with the cylinder'lock 114, the key isturned so that the member 118 assumes the position as shown in FIGS. 2,3, 5, and 6. In this position the surface 124 is to the right as viewedin the drawings and the leaf spring 154 forces the plate 132 upwardlyuntil the upper surface of portion 138 contacts surface 124.Furthermore, the slope angle of the surface 128 is closer to thevertical than the slope of the portion 134 so that there is no contactbetween these sections in this position. In this position, when thehandle 64 is turned, rearward movement of the bolt is stopped becausethe forward edge 136 engages the lip (FIG. 2) 89 of the bolt 84.Additional security can be provided by passing the hasp 80 of a standardpadlock 82 through the apertures 76, 78.

However, in these positions, it is still possible to open the latch,by-passing both of the locks, from the interior of the box. This is doneby rotating the handle 178 of the-lever 18 in either direction,clockwise or counterclockwise. This causes the spindle to rotate andsince the spindle is secured to the cam hub within opening 174, which isnon-circular, the cam itself turns in either direction. As a result,either of the surfaces 168, 170 may bear against the rear cam followershoulder. 100 to initiate retraction of the bolt. Simultaneously, theforward shoulder 172 contacts the shoulder 142 of the tongue 132 both ofwhich are somewhat rounded to insure proper co-action. Continuedmovement of the cam causes the plate to be forced downwardly so that theedge 136 is forced below the lip 89, and this allows the bolt to moverearwardly. Because of the forward length of the aperture 90, the finger72 also does not prevent sufficient rearward movement of the bolt for itto disengage from the strike.

All that is necessary for the system to work is that the force on theshoulder 100 overcome the force within the compression spring-Since thehandle is not actuated, there is no need for any complicated mechanismto release the handle. The only moving element within the latch is thebolt itself and the cam, everything else being completely by-passed.

The tongue and the leaf spring are fabricated from strong durablematerials, and thus the whole unit will be capable of extended usewithout break-down.

The terms and expressions which have been employed here are used asterms of description and not of limitation and there is no intention inthe use of such terms and expressions, of excluding equivalents of thefeatures shown and described or portions thereof, it being recognizedthat various modifications are possible within the scope of theinvention claims.

What is claimed is:

1. An improved slam-style safety lock for enclosed environments allowingegress from the interior when the exterior lock has been actuated,comprising:

a. a retractable bolt b. means for housing the bolt, the housing havingan opening, to allow passage of the bolt therefrom c. means to securethe housing means to a door allowing access into the environment d.keeper means on the door jamb in alignment with and receiving a portionof the bolt in its normal extended position when the door is closed e.means mounted on the housing means for actuating the bolt between itsengagement position with the keeper means to which it is normallyyieldingly biased and its retracted position, out of engagement with thekeeper means f. the bolt having an aperture, cam means within saidaperture g. hand grip and spindle means movably mounted on the doorinside the environment, the spindle means passing through the door andengaging the cam means for retracting the bolt from inside theenvironment without utilizing the actuating means,

h. a locking plate positioned inwardly of the bolt, the

plate having an outwardly extending forward portion, the bolt having alip adjacent the forward portion i. means urging the plate outwardly andparticularly the forward portion into the path of travel of the bolt andengagement with the lip j. locking means positioned within the housingand extending inwardly toward the locking plate, the locking means inits locking position being free of the locking plate which preventsopening of the lock from the exterior, and the locking means having asecond position which pushes the locking plate out of the path of travelof the bolt so that the lock may be actuated from the exterior k. andmeans operable only from inside the environment for pushing the lockingplate inwardly to a position free of said lip, thus allowingunobstructed rearward movement of the bolt by actuation of the hand gripand spindle means even when such movement is precluded from theexterior.

2. The invention according to claim I, the means urging the plateoutwardly, being a leaf spring positioned inwardly of the locking plate.

3. The invention according to claim 1, the locking plate having ashoulder adjacent the forward portion of said cam means.

4. The invention according to claim 3, the cam means having a forwardlyextending shoulder facing and adjacent to the shoulder of the lockingplate so that upon actuation of the cam means in either rotationaldirection, the forward shoulder of the cam means contacts the shoulderof the locking plate and upon extended rotational movement, forces thelocking plate inwardly to a position out of the path of travel of thelip of the bolt.

5. The invention according to claim 4, the locking plate having asubstantially planar portion placed in between and connecting theshoulder and the outwardly extending forward portion, and then havinganother rearwardly extending substantially planar portion having anopening defined therein to allow passage of the spindle-means intoengagement with the cam means.

6. The invention according to claim 5, the means urging the plateoutwardly, being a leaf spring positioned inwardly of the locking plate.

7. The invention according to claim 6, the leaf spring having anoutwardly extending forward portion and a central portion dependingrearwardly therefrom, having an aperture defined therein to allowpassage of the spindle means, and an outwardly and rearwardly extendingrear portion, the forward and rear portions engaging the inward surfacesof the locking plate, and the forces being translated from the leafspring to continually urge the locking plate outwardly.

1. An improved slam-style safety lock for enclosed environments allowingegress from the interior when the exterior lock has been actuated,comprising: a. a retractable bolt b. means for housing the bolt, thehousing having an opening, to allow passage of the bolt therefrom c.means to secure the housing means to a door allowing access into theenvironment d. keeper means on the door jamb in alignment with andreceiving a portion of the bolt in its normal extended position when thedoor is closed e. means mounted on the housing means for actuating thebolt between its engagement position with the keeper means to which itis normally yieldingly biased and its retracted position, out ofengagement with the keeper means f. the bolt having an aperture, cammeans within said aperture g. hand grip and spindle means movablymounted on the door inside the environment, the spindle means passingthrough the door and engaging the cam means for retracting the bolt frominside the environment without utilizing the actuating means, h. alocking plate positioned inwardly of the bolt, the plate having anoutwardly extending forward portion, the bolt having a lip adjacent theforward portion i. Means urging the plate outwardly and particularly theforward portion into the path of travel of the bolt and engagement withthe lip j. locking means positioned within the housing and extendinginwardly toward the locking plate, the locking means in its lockingposition being free of the locking plate which prevents opening of thelock from the exterior, and the locking means having a second positionwhich pushes the locking plate out of the path of travel of the bolt sothat the lock may be actuated from the exterior k. and means operableonly from inside the environment for pushing the locking plate inwardlyto a position free of said lip, thus allowing unobstructed rearwardmovement of the bolt by actuation of the hand grip and spindle meanseven when such movement is precluded from the exterior.
 2. The inventionaccording to claim 1, the means urging the plate outwardly, being a leafspring positioned inwardly of the locking plate.
 3. The inventionaccording to claim 1, the locking plate having a shoulder adjacent theforward portion of said cam means.
 4. The invention according to claim3, the cam means having a forwardly extending shoulder facing andadjacent to the shoulder of the locking plate so that upon actuation ofthe cam means in either rotational direction, the forward shoulder ofthe cam means contacts the shoulder of the locking plate and uponextended rotational movement, forces the locking plate inwardly to aposition out of the path of travel of the lip of the bolt.
 5. Theinvention according to claim 4, the locking plate having a substantiallyplanar portion placed in between and connecting the shoulder and theoutwardly extending forward portion, and then having another rearwardlyextending substantially planar portion having an opening defined thereinto allow passage of the spindle means into engagement with the cammeans.
 6. The invention according to claim 5, the means urging the plateoutwardly, being a leaf spring positioned inwardly of the locking plate.7. The invention according to claim 6, the leaf spring having anoutwardly extending forward portion and a central portion dependingrearwardly therefrom, having an aperture defined therein to allowpassage of the spindle means, and an outwardly and rearwardly extendingrear portion, the forward and rear portions engaging the inward surfacesof the locking plate, and the forces being translated from the leafspring to continually urge the locking plate outwardly.
 8. The inventionaccording to claim 1, the locking means including a cylinder lock with atruncated cylindrical section extending therefrom, the greatest lengththereof extending to the rear in the locking position, and allowing thelocking plate to be urged outwardly and into the path of travel of thelip of the bolt, and the longest length of the cylindrical portionextending towards the front during unlocking position to force thelocking plate inwardly and out of the path of travel of the lip of thebolt.